1nbd_can_meta_context(3)             LIBNBD             nbd_can_meta_context(3)
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NAME

6       nbd_can_meta_context - does the server support a specific meta context?
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SYNOPSIS

9        #include <libnbd.h>
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11        int nbd_can_meta_context (
12              struct nbd_handle *h, const char *metacontext
13            );
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DESCRIPTION

16       Returns true if the server supports the given meta context (see
17       nbd_add_meta_context(3)).  Returns false if the server does not.  It is
18       possible for this command to fail if meta contexts were requested but
19       there is a missing or failed attempt at NBD_OPT_SET_META_CONTEXT during
20       option negotiation.
21
22       The single parameter is the name of the metadata context, for example
23       "LIBNBD_CONTEXT_BASE_ALLOCATION".  <libnbd.h> includes defined
24       constants for well-known namespace contexts beginning with
25       "LIBNBD_CONTEXT_", but you are free to pass in other contexts.
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27       This call does not block, because it returns data that is saved in the
28       handle from the NBD protocol handshake.
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RETURN VALUE

31       This call returns a boolean value.
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ERRORS

34       On error -1 is returned.
35
36       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
37       of the error.
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39       The following parameters must not be NULL: "h", "metacontext".  For
40       more information see "Non-NULL parameters" in libnbd(3).
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HANDLE STATE

43       The handle must be negotiating, or connected with the server, or shut
44       down, otherwise this call will return an error.
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VERSION

47       This function first appeared in libnbd 1.0.
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49       If you need to test if this function is available at compile time check
50       if the following macro is defined:
51
52        #define LIBNBD_HAVE_NBD_CAN_META_CONTEXT 1
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SEE ALSO

55       nbd_add_meta_context(3), nbd_aio_block_status(3), nbd_block_status(3),
56       nbd_create(3), nbd_opt_info(3), nbd_opt_set_meta_context(3),
57       nbd_set_request_meta_context(3), "Flag calls" in libnbd(3), libnbd(3).
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AUTHORS

60       Eric Blake
61
62       Richard W.M. Jones
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65       Copyright Red Hat
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LICENSE

68       This library is free software; you can redistribute it and/or modify it
69       under the terms of the GNU Lesser General Public License as published
70       by the Free Software Foundation; either version 2 of the License, or
71       (at your option) any later version.
72
73       This library is distributed in the hope that it will be useful, but
74       WITHOUT ANY WARRANTY; without even the implied warranty of
75       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
76       Lesser General Public License for more details.
77
78       You should have received a copy of the GNU Lesser General Public
79       License along with this library; if not, write to the Free Software
80       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
81       02110-1301 USA
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85libnbd-1.16.5                     2023-09-26           nbd_can_meta_context(3)
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